The objectives of this application are to: 1. Reduce rates of nosocomial infections; 2. Define the magnitude of the problem of nosocomial infections in a representative sample of acute care hospitals using a standardized, prospective data collection system in each institution (descriptive epidemiology); 3. Identify both modifiable and non-modifiable risk factors for nosocomial infection (analytical epidemiology); 4. execute a controlled intervention trial based upon modifiable risk factors identified in the study to determine to what extent nosocomial infections are preventable in the context of "usual" hospital infection control programs (experimental epidemiology); 5. measure the effectiveness (practicality, compliance) of specific interventions in reducing nosocomial infection rates. METHODS: A standardized, prospective surveillance system has been established in 12 non-governmental acute care hospitals in Rhode Island. The baseline surveillance is carried out by inplace hospital infection control personnel on carefully selected random samples of patients in each hospital. At the conclusion of the baseline surveillance period, hospital specific interventions will be developed. During the period of intervention, rates of infection and compliance with the intervention will be monitored using the same surveillance system. Comparisons between hospitals, appropriately corrected for differences in types of patients and LOS distribution will be made to control for similar trends and to describe the overall effect of the interventions on the statewide rate of nosocomial infections.